"nrfjprog -e" renders our board unconfigurable

RE: "nrfjprog -e" renders our board unconfigurable

Jared — Fri, 16 Oct 2020 09:07:27 GMT

Which nrfjprog version are you using? Can you update it to the newest version.

Could you try the workaround I mentioned in a previous reply, and just to be sure, could you pass the --family nrf52 argument with the log option like this and upload the log after you've applied the workaround:

nrfjprog --family nrf52 --eraseall --log

RE: "nrfjprog -e" renders our board unconfigurable

ToBe — Fri, 16 Oct 2020 08:56:25 GMT

Thanks for the suggestion but as stated in the original post, all the nrfjprog commands (including --recover) lead to the same error message.

ERROR: nrfjprog could not identify the target device. This may be due to an
ERROR: invalid family argument, a problem with your device, or nrfjprog may
ERROR: not yet support your device.
ERROR: Please check the family argument passed, or upgrade nrfjprog to a more
ERROR: recent version.

RE: "nrfjprog -e" renders our board unconfigurable

Jared — Thu, 15 Oct 2020 14:02:25 GMT

aha, seems like you're also using the APPROTECT feature. The APPROTECT feature secures the IC from any external read, erase, or write operation after it has been activated. It does this by disabling the debugging interface. The only way the device can be recovered after the APPROTECT has been activated is by issuing a nrfjprog --recover command. Note that this will erase everything on the chip and set it back to default mode.

regards

Jared

RE: "nrfjprog -e" renders our board unconfigurable

ToBe — Thu, 15 Oct 2020 13:48:08 GMT

Yes, configured for normal mode.
We're not sure how to short VDD but we'll look into it.

We noticed that when trying to compile via Segger Studio, we get the following message (If we accept it just carries on to give the "no idcode..." error) :

RE: "nrfjprog -e" renders our board unconfigurable

Jared — Thu, 15 Oct 2020 12:48:58 GMT

Hmm, that should support DUTs at 1V8. Nevertheless could you try the suggested method in my previous reply. And address this question:

[quote user="Jared"]How was the board configured when you initially programmed it? Normal mode? [/quote]

RE: "nrfjprog -e" renders our board unconfigurable

ToBe — Thu, 15 Oct 2020 12:11:00 GMT

We're using a Segger Jlink Educational version.

RE: "nrfjprog -e" renders our board unconfigurable

Jared — Thu, 15 Oct 2020 11:31:20 GMT

Which J-link model are you using? Maybe it can't program DUTs at 1V8. It doesn't seem that you have anything that is dependent on the voltage being 3V3 in your design that would hinder re-flashing.

Could you try shorting VDD and VDDH (configure the board in Normal mode) and supply the device directly with 3V3, which is still within Normal mode conditions. Then proceed with programming the board with an application that writes to the UICR?

regards

Jared

RE: "nrfjprog -e" renders our board unconfigurable

ToBe — Thu, 15 Oct 2020 10:56:08 GMT

Hey, schematics attached.

RE: "nrfjprog -e" renders our board unconfigurable

Jared — Thu, 15 Oct 2020 08:56:31 GMT

Hmm..

So you're not managing to write to the UICR after the erase, and you're still not able to identify the board with nrfjprog? How is your custom board dependent on the VDD being 3V3? What happens when REG0 is 1.8V, is there some external part on your board that is supplied by the REG0 output of the nRF52840? Would not supplying this properly block SWD from communication with nRF52840 on your board? As you can tell, I could need a better overview of your board, a Schematic would help alot!

[quote user="ToBe"]We did set the board in High voltage mode prior to using erase[/quote]

How was the board configured when you initially programmed it? Normal mode? Is there an option to short VDD and VDDH which would effectively set the board in Normal mode and then flash the application that writes to the REG0 register?

regards

Jared

RE: "nrfjprog -e" renders our board unconfigurable

ToBe — Wed, 14 Oct 2020 13:47:20 GMT

Your suspicion is spot on. We did set the board in High voltage mode prior to using erase. We set REG0 with the command:

nrfjprog --memwr 0x10001304 (UICR.REGOUT0 address) --val 0xFFFFFFFD (3V3 setting)

Trying to set it after erase results in:

ERROR: Low voltage detected at the target. Please make sure the device is
ERROR: properly supplied.

So, what do you suggest doing?

RE: "nrfjprog -e" renders our board unconfigurable

Jared — Wed, 14 Oct 2020 12:06:56 GMT

Hi,

My initial suspicion is that your design is not using the default output value of REG0 which is 1.8V. A nrfjprog --eraseall command will erase everything from the IC including the UICR. The UICR contains the REG0 register which sets the output of the first regulator. Are you using the board in High voltage mode and have you configured REG0 to something else then the default value?

regards

Jared